Please understand the reason for having a gelding contract is to make sure that pet quality colts don't end up as breeding stallions.
My whole mission in breeding is to better the breed.
If for some reason a colt is not castrated before he leaves, the following contract will be put into place if sold on a gelding contract.

and how it works.

As the buyer, you take possestion of the colt, intact. Buyer does not get any papers with the horse. The buyer has the colt gelded and sends me the certificate from the veterinarian that he's been cut. I then submit the papers to the association(s) and have them changed to Gelding. Once the papers come back I then forward them to the buyer with the appropriate transfer forms.